1. Field of the Invention
The present invention relates to a display apparatus and, more particularly, to a display apparatus having a rotating display panel provided with a polarizer thereon so as to generate a three dimensional (3-D) image that can be viewed by a viewer wearing polarized glasses.
2. Description of Related Art
A conventional electronic display board is composed of a very large number of light emitting units, such as light emitting diodes (LEDs), fluorescent lamps, or liquid crystal displays (LCDs). For example, in the case of a 500xc3x97500 pixel display board, if the board operates in a monochromatic display mode, it will require a total amount of 250,000 LEDs. Further, if it displays three colors, the required number of LEDs will be tripled. Obviously, more LEDs will increase the costs of the display board and result in higher maintenance cost.
In order to overcome the aforementioned disadvantages, the same applicant disclosed a display apparatus having a rotating display panel as shown in FIG. 1, which was issued as U.S. Pat. No. 5,818,401 on Oct. 6, 1998. The entire content of that patent is incorporated herein by reference.
Referring to FIG. 1, a conventional display apparatus 100 comprises a pedestal 10, a cylindrical display body 20 rotatably mounted on the pedestal 10 and multiple, vertical, light emitting arrays 11 are secured at equal distances on the wall of the cylindrical body 20. Each of the light emitting arrays 11 is composed of multiple light emitting units such as LEDs. When the display body 20 rotates at a speed that a viewer""s eyes cannot distinguish the individual light emitting arrays 11 and the LEDs are sequentially turned on, a viewer sees the corresponding information on the rotating body 20 due to the persistence of vision. In order to achieve a steady picture without flickering, the light emitting arrays 11 and the rotating speed of the display body 20 have to meet certain conditions. In a normal case, the minimum frame rate is 24 frames per second. For this display apparatus 100, the frame rate is the product of the number of light emitting arrays and the rotating speed of the display body. Thus, if there were eight light emitting arrays, the rotational speed of the display body would have to be 3 revolutions or more per second.
Furthermore, as described in U.S. Pat. No. 5,818,401, the rotatable display body of the display apparatus may be configured differently. In a first variant, the light emitting arrays are equally spaced on the outside of a spherical display body, and thus a spherical display panel will be achieved when the display body rotates. In a second variant, the light emitting arrays are placed on a planar surface of a roller body, and each of the arrays is equally spaced radially such that a circular display panel is achieved when the display body rotates.
Although U.S. Pat. No. 5,818,401 provides an improved display apparatus having a rotating display panel so as to generate an image displayed on the rotating display body due to the persistence of vision, the displayed image is simply a plane image, i.e., a two dimensional (2-D) image.
In the past, a three dimensional (3-D) image such as a conventional 3-D movie could be generated on a planar display panel through a specific process based on known optical technologies. Conventionally, polarizers having different polarization directions are provided on the lens of two projectors, respectively. In this arrangement, the images for the left and right eyes of a viewer, differently polarized in two polarization directions, are projected on the screen and reflected to a viewer""s eyes, such that the viewer can see the 3-D image through the polarized glasses.
In addition, an optical valve is utilized to synchronously view the left and right images so as to generate an improved 3-D visual effect. However, the glasses formed with the optical valve are expensive and less convenient to use.
Accordingly, one object of the present invention is to provide a display apparatus having a rotating display panel that can generate a 3-D image when viewed by a viewer wearing polarized glasses.
Another object of the present invention is to provide a display apparatus having a rotating display panel that can generate a colorful image.
A further object of the present invention is to provide a display apparatus having a rotating display panel that reduces the costs of the display panel and the resultant maintenance cost.
A display apparatus comprises a pedestal; a display body rotatably mounted on the pedestal; multiple light emitting arrays, each light emitting array further comprising multiple light emitting units and being equally spaced on a surface of the display body to display information when the display body rotates; and a polarizer on each of the light emitting arrays, the polarization directions of adjacent polarizers being perpendicular.
The polarizers on odd light emitting arrays are horizontally polarized, and the polarizers on even light emitting arrays are vertically polarized.
In accordance with one aspect of the present invention, the display body of the display apparatus is cylindrical, and the light emitting arrays are arranged axially and spaced equally on the wall of the cylindrical display body.
The display body of the display apparatus can be spherical with each of the light emitting arrays equally spaced on the surface of the spherical display body.
The display body of the display apparatus can be a roller body with each of the light emitting arrays equally spaced radially on a planar surface of the roller display body.
Other objects, advantages and features of the invention will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings.